Active Semiconductor Layer Research Articles

Low-Temperature Solution-Processed Thin SnO2/Al2O3Double Electron Transport Layers Toward 20% Efficient Perovskite Solar Cells

We present planar perovskite solar cells incorporating thin SnO2/Al2O3 double electron transport layers between the perovskite and an indium tin oxide bottom electrode. When measured under 1 sun illumination, we obtained a maximum power conversion efficiency (PCE) of 20.1% and a steady state efficiency of 17.8% for the best cell. These values were ∼20%–30% higher in relative terms than those of cells with SnO2 only (i.e., a maximum PCE of 15.3% and a steady state PCE of 14.9%). Insertion of the thin UV-irradiated solution-processed nanoparticle Al2O3 interlayer effectively enhanced the wettability of the electron transport layer, provided enhanced interface area, as well as a lower work function, leading to improved charge extraction. Incorporation of an Al2O3 layer between the perovskite and SnO2 layers also improved the rectification ratios of the diodes as well as both series and shunt resistances. Our devices are fabricated using fully solution-processed transport and active semiconducting layers processed at low temperatures (≤150 °C).

Improved spectral and temporal response of MSM photodetectors fabricated on MOCVD grown spontaneous AlGaAs superlattice

A co-planar metal-semiconductor-metal nonsymmetrical back to back Schottky diode photodetector using natural superlattice AlGaAs grown by metalorganic vapor phase epitaxy on GaAs (100) has been reported. The detection efficiency and photoresponse of the superlattice based device are found significantly superior compared to the one based on high temperature annealed homogeneous AlGaAs. Under a forward bias of 1 V, the peak values of responsivity, detectivity and sensitivity were 10.133 mA/W, 7.6 × 1011 cmHz1/2W−1, 81.06 cm2/W and 1.14 mA/W, 7.05 × 1010 cmHz1/2W−1, 2.82 cm2/W for the device with as-grown natural superlattice and homogeneous composition of AlGaAs, respectively. Besides, the device with natural superlattice structure showed much faster response to the pulsed light with rise and decay time of 560 μs and 1 ms as compared to 2 and 7 ms, respectively for the device with disordered bulk AlGaAs. The superior spectral and temporal characteristics of the device are explained by a model based on a third diode representing the net effect due to the superlattice modulations along with two Schottky diodes at the metal-semiconductor junctions. The third barrier, which is basically due to the periodic modulation in aluminium composition, plays an important role in enhancement of the photocurrent owing to the activation of the superlattice channels under light while keeping the dark current small. The fast sweeping of the photogenerated carries by the intrinsic electric field at the heterointerfaces in the active semiconducting layer makes the characteristic times of the device with the superlattice structures much smaller than one with homogeneous AlGaAs. Degradation in photoresponse and speed is attributed to the interdiffusion as an effect of thermal annealing.

Citrus fruit peels extracts as light harvesters for efficient ZnO-based dye-sensitized solar cells

Our voracious consumption of fossil fuels at an exponentially increasing rate has led to global warming and climate change. As a result of these problems, it is crucial to exploreother sources of clean energy. The natural pigmentsextraction and the performancedetermination in Dye-Sensitized Solar Cells (DSSCs)from fruit peels of citrus were presented in this paper. Extraction of natural dye of citrus fruit peels of Citrus paradisi, Citrus sinensis, Citrus limonumandCitrus tangelo were employed as light sensitizers in fabricating ZnO-based DSSCs. The natural pigments extracts characteristics were analyzedby UV-Vis absorption, Fourier transforms infra-red (FTIR) and Photoluminescence spectroscopy techniques. The semiconductor active layer material was synthesized and analyzed. The characteristics of photo-voltaic parameters for the invented DSSCs were studied under simulated sunlight. The presence of chlorophyll derivative in most of the extracted dyes is evident as the core pigments with additional accessory pigments. The conversion efficiencies of sunlight to electrical energy of pheophytin ‘a’ dye ZnO based solar cells are calculated to be 0.028%, 0.013%, 0.004% and 0.022% for Citrus paradisi, Citrus sinensis, Citrus limonumand Citrus tangelo, respectively. Better performance of photo-sensitized was observed for the extracts of Citrus paradisicompared to the other extracts and this may be owing to the better charge transfer between the pigments of Citrus paradisi and surface of ZnOphotoactive layer. The conversion of visible light to electricitywas produced from natural pigments and ZnO photoactive layerbased DSSCs, resulted into superb photo-electric characteristics.

Hysteresis control by varying Ta2O5-nanoparticles concentration in PMMA-Ta2O5 bilayer gate dielectric of hybrid-organic thin film transistors

Abstract In this paper, we report the fabrication of a series of top-gate bottom-contact hybrid organic thin film transistors based on solution-processed semiconductors and dielectric layers on a glass substrate. Semiconductor active layers were based on a mixture of [6,6]-phenyl C61-butyric acid methyl ester (PCBM) mixture and poly (3-hexylthiophene) (P3HT), whereas gate dielectric layers were based on PMMA mixed with various concentrations of high-k Ta2O5 inorganic particles. Experimental investigation indicated that the hysteresis phenomenon of the devices can be governed by changing of the Ta2O5 concentration in PMMA-Ta2O5 nanocomposites gate dielectric layer. In addition, significant enhancement of electron transport was also observed with the increase of Ta2O5 inorganic particles concentration in the gate layer, which arises from the change of the charge transport from unipolar to ambipolar type. The fabricated OTFTs, with significant hysteresis variation as a function of Ta2O5 nanoparticles content in PMMA-Ta2O5 gate dielectrics, prove particularly promising in consideration of possible use for low-cost nonvolatile memory elements and sensing array applications.

A Solid‐State Aqueous Electrolyte‐Gated Field‐Effect Transistor as a Low‐Voltage Operation Pressure‐Sensitive Platform

AbstractFlexible pressure sensors are increasingly impacting a wide variety of novel applications such as wearable health care sensors, in vivo monitoring, and even artificial skin. As a fundamental device component, organic field‐effect transistors (OFETs) are of great interest due to their inherent advantages related to low‐cost solution fabrication processes and compatibility with plastic substrates. During OFET fabrication, it is almost impossible to avoid the water traces in the organic semiconductor (OSC) active layer, especially when ambient solution processing techniques are employed. Water exhibits a strong influence on the electrical performance in OFETs, such as hysteresis and nonideal transfer characteristics. Here, it is shown that the presence of water in OSCs also results in pressure‐sensitive devices caused by the modification of the water dipole alignment. This exciting phenomenon is exploited in a novel OFET, namely, hydrogel‐based electrolyte‐gated organic field‐effect transistor (HYGOFET), where a soft water‐based hydrogel layer is employed as a dielectric layer. The hydrogel layer plays two major contributions: 1) providing a constant saturated humidity environment and 2) reducing the operation voltage. The HYGOFET exhibits a high electrical performance and relative long‐term stability. Importantly, this device also exhibits an excellent pressure response in the low‐pressure regime (<10 kPa) working with a very low power consumption.

Tuning dielectric-semiconductor interfacial properties in organic phototransistors for ultralow light detection

The quality of the dielectric-semiconductor interface plays a very crucial role in determining the photosensory performances of the organic field effect transistors. Herein, we have investigated the influence of polymer molecular weight on the photosensing behaviour of the organic transistors. In this study, we find high molecular weight PMMA to be more effective as gate dielectric in phototransistor applications compared to the low molecular weight PMMA due to the better morphological arrangements of the active semiconducting layer on top of its surface. The maximum values of photosensitivity and responsivity improved substantially from 3.5 × 10 4 and 8.3 × 10 3 A/W in the low molecular weight PMMA devices to 10 5 and 6.9 × 10 4 A/W in the high molecular weight PMMA devices, respectively, under same intensity light irradiation. Moreover, we have also proposed a simple, yet highly efficient interface modification technique to enhance the photosensitivity of the transistors under low light illumination through the plasma treatment of the dielectric layer. After the interface modification of the high molecular weight PMMA devices, the photosensitivity value enhanced significantly from 3.67 × 10 2 to 7.08 × 10 3 under an ultralow optical power of 5 μW/cm 2 . Post interface modification improvements in the device photosensitivity values were attributed to the plasma induced generation of polar surface functionalities which effectively enhance the number of free holes in the channel region by trapping the photo-generated electrons at the interface. This report, thus, represents a step forward towards improving the performance of the phototransistors for their applications in high performance organic optoelectronic devices. • Polymer molecular weight influenced transistor photoresponse has been explored. • Semiconductor grain structure strongly correlates with the device photoresponse. • Strategy of dielectric air plasma treatment has been demonstrated. • Optimum plasma treatment time has been reached to achieve ultralow light sensitivity.

High-Performance Thin-Film Transistors of Quaternary Indium-Zinc-Tin Oxide Films Grown by Atomic Layer Deposition.

A new deposition technique is required to grow the active oxide semiconductor layer for emerging oxide electronics beyond the conventional sputtering technique. Atomic layer deposition (ALD) has the benefits of versatile composition control, low defect density in films, and conformal growth over a complex structure, which can hardly be obtained with sputtering. This study demonstrates the feasibility of growing amorphous In-Zn-Sn-O (a-IZTO) through ALD for oxide thin-film transistor (TFT) applications. In the ALD of the a-IZTO film, the growth behavior indicates that there exists a growth correlation between the precursor molecules and the film surface where the ALD reaction occurs. This provides a detailed understanding of the ALD process that is required for precise composition control. The a-IZTO film with In/Zn/Sn = 10:70:20 was chosen for high-performance TFTs, among other compositions, regarding the field-effect mobility (μFE), turn-on voltage ( Von), and subthreshold swing (SS) voltage. The optimized TFT device with the a-IZTO film thickness of 8 nm revealed a high performance with a μFE of 22 cm2 V-1 s-1, Von of 0.8 V, and SS of 0.15 V dec-1 after annealing at 400 °C for 30 min. Furthermore, an emerging device such as a vertical channel TFT was demonstrated. Thus, the a-IZTO ALD process could offer promising opportunities for a variety of emerging oxide electronics beyond planar TFTs.

A Pentacene -Based Organic Mis Structures

Organic devices based on pentacene thin film are demonstrated. Gold nanoparticles were used as the charge storage elements while pentacene has been used as the active semiconductor layer of Metal-Insulator-Semiconductor (MIS) structures. Polymethylmethacrylate (PMMA) formed the gate insulator. Four devices at different evaporation rates were fabricated and characterised by the atomic force microscopy and electrical characteristics. An optimal deposition rate was identified and supporting topographical images are presented. The device performance strongly correlates with the surface morphology, and the structural properties of the organic thin films have been investigated. The Atomic Force Microscopy (AFM) investigation of very slow evaporated pentacene showed larger grain sizes. Evaporating of gold electrodes on pentacene layers proved to change the morphology of the pentacene surface. The characteristics of bottom contact structures showed much-improved pentacene structures.

Symmetry-Controlled Reversible Photovoltaic Current Flow in Ultrathin All 2D Vertically Stacked Graphene/MoS2/WS2/Graphene Devices.

Atomically thin vertical heterostructures are promising candidates for optoelectronic applications, especially for flexible and transparent technologies. Here, we show how ultrathin all two-dimensional vertical-stacked type-II heterostructure devices can be assembled using only materials grown by chemical vapor deposition, with graphene (Gr) as top and bottom electrodes and MoS2/WS2 as the active semiconductor layers in the middle. Furthermore, we show that the stack symmetry, which dictates the type-II directionality, is the dominant factor in controlling the photocurrent direction upon light irradiation, whereas in homobilayers, photocurrent direction cannot be easily controlled because the tunnel barrier is determined by the doping levels of the graphene, which appears fixed for top and bottom graphene layers due to their dielectric environments. Therefore, the ability to direct photovoltaic current flow is demonstrated to be only possible using heterobilayers (HBs) and not homobilayers. We study the photovoltaic effects in more than 40 devices, which allows for statistical verification of performance and comparative behavior. The photovoltage in the graphene/transition-metal dichalcogenide-heterobilayer/graphene (Gr/TMD-HB (MoS2/WS2)/Gr) increases up to 10 times that generated in the monolayer TMD devices under the same optical illumination power, due to efficient charge transfer between WS2 and MoS2 and extraction to graphene electrodes. By applying external gate voltages ( Vg), the band alignment can be tuned, which in turn controls the photovoltaic effect in the vertical heterostructures. The tunneling-assisted interlayer charge recombination also plays a significant role in modulating the photovoltaic effect in the Gr/TMD-HB/Gr. These results provide important insights into how layer symmetry in vertical-stacked graphene/TMD/graphene ultrathin optoelectronics can be used to control electron flow directions during photoexcitation and open up opportunities for tandem cell assembly.

Three-terminal memtransistors based on two-dimensional layered gallium selenide nanosheets for potential low-power electronics applications

A multi-terminal hybrid system named memtransistor has recently been proposed by combining the concepts of both memristor and field effect transistor (FET) with two-dimensional (2D) layered materials as the active semiconductor layer. In the memtransistors, the gate voltages are capable of modulating not only the transport properties of the fabricated FET, but also the resistive switching (RS) behaviors of the memristor. Herein, we employ mechanically exfoliated 2D layered GaSe nanosheets to prepare GaSe based three-terminal memtransistors. By using Ag as the electrodes, the memristor exhibits non-volatile bipolar RS characteristics. More importantly, under exposure to air for one week, the RS behaviors are dramatically enhanced with the ON/OFF ratio reaching up to 5.3 × 105 and ultralow threshold electric field of ~3.3 × 102 V cm−1. The ultralow threshold electric field of GaSe based memristor could be related to the low migration energy of the intrinsic Ga vacancy in p-type GaSe. Moreover, the GaSe-based memristor shows long-term retention (~104 s) and high cycling endurance (~5000 cycles) simultaneously. Hence, the fabricated three-terminal 2D GaSe memtransistors possess high performance with large switching ratios, ultralow threshold electric field, good endurance and long-term retention. Furthermore, the device demonstrates gate tunability in RS characteristics, suggesting the promising applications in multi-terminal electronic devices with low power consumption and complex functionalities, ranging from non-volatile memory, logic device to neuromorphic computing.

High temperature-stability of organic thin-film transistors based on quinacridone pigments

Abstract Robust organic thin-film transistors (OTFTs) with high temperature stability allow device integration with mass production methods like thermoforming and injection molding, and enable operation in extreme environment applications. Herein we elaborate a series of materials to make suitable gate dielectric and active semiconductor layers for high temperature stable OTFTs. We employ an anodized aluminum oxide layer passivated with cross-linked low-density polyethylene (LD-PE) to form a temperature-stable gate capacitor. As the semiconductor, we use quinacridone, an industrial organic colorant pigment produced on a mass scale. Evaporated MoOx/Ag source and drain electrodes complete the devices. Here we evaluate the performance of the OTFTs heating them in air from 100 °C in 25 °C increments up to 225 °C, holding each temperature for a period of 30 minutes. We find large differences in stability between quinacridone and its dimethylated derivative, with the former showing the best performance with only a factor of 2 decline in mobility after heating at 225 °C, and unaffected on/off ratio and threshold voltage. The approach presented here shows how industriallys calable fabrication of thermally robust OTFTs can be rationalized.

Stability of hydrogenated amorphous carbon thin films for application in electronic devices

In this study, hydrogenated amorphous carbon (a-C:H) films are investigated for electronic applications as an insulating layer. a-C:H films were deposited using Radio Frequency-Plasma Enhanced Chemical Vapour Deposition (RF-PECVD) technique at room temperature. For the first time, the properties of a-C:H films as a function of annealing temperature is investigated, with a focus on their electrical and optical properties. This study shows that a-C:H films are stable up to 450 °C. This investigation will facilitate the use of a-C:H films as an insulating layer where the semiconductor active layers are deposited at higher temperatures (e.g. amorphous silicon deposited around 300 °C for thin film transistor TFTs). In addition to understanding the electrical and optical properties of annealed a-C:H films, we have further explored and studied its suitability in Flash-type memory devices. Various forms of diamond-like carbon are considered to have a high chemical resistance; no extensive data are available in the literature on this subject. The stability of a-C: H thin films with variousreactive chemicals, commonly used in organic/printable electronic devices, is also investigated in this work. The findings may provide opportunities for adoption/integration of a-C:H in hybrid organic-inorganic electronic devices.

Electron – Phonon interaction to tune metal – Semiconductor junction characteristics: Ultralow potential barrier and less non-thermionic emission

We present a two-step facile method to prepare Ni2O3 coral–like and flower–like nanostructures first time followed by structural, optical characterizations by XRD, FESEM, HRTEM, Raman, luminescence spectroscopy etc. We also report rectifying I–V characteristics of Ni2O3 nanostructures/Al based metal–semiconductor junction with ultralow turn-on voltages (0.36 V), potential barrier (0.33 eV), very ideal thermionic current (η = 1.11). Photo-responsive character illustrates that the junction devices could be a promising material for light sensing application. Parameters like series resistance (111.4 Ω), electron mobility (16.73 × 10−10 m2V1s−1), diffusion length (5.13 × 10−7 m), density of states (3.09 × 1040 eVm−3) etc. have been evaluated and it is discussed that the defect (Ni3+ vacancy) induced electron–phonon interaction within the active semiconducting layer plays the crucial role to determine these parameters. Most importantly, it has been identified that the charge-transport across the junction follows non-adiabatic mechanism. Our results suggest a new insight into current transport mechanism that may be generalized to understand microstructural, defect dependence MS junctions.

Perylene-Based Liquid Crystals as Materials for Organic Electronics Applications.

Columnar phases formed by the stacking of disclike molecules with an intimate π-π overlap forms a 1D pathway for the anisotropic charge migration along the columns. Columnar phases have great potential in organic electronic devices to be utilized as active semiconducting layers in comparison to organic single crystals or amorphous polymers in terms of processability, ease of handling, and high charge carrier mobility. Intelligent molecular engineering of perylene and its derivatives provided access to tune the physical properties and self-assembly behavior. The columnar phase formed by perylene derivatives has great potential in the fabrication of organic electronic devices. There are several positions on the perylene molecule, which can be functionalized to tune its self-assembly, as well as optoelectronic properties. Thus, many liquid-crystalline molecules stabilizing the columnar phase, which are based on perylene tetraesters, perylene diester imides, and perylene bisimides, have been synthesized over the years. Their longitudinal and laterally extended derivatives, bay-substituted derivatives exhibiting a columnar phase, are reported. In addition, several liquid-crystalline oligomers and polymers based on perylene derivatives were also reported. All such modifications provide an option to tune the energy levels of frontier molecular orbitals with respect to the work function of the electrodes in devices and also the processability of such materials. In this feature article, we attempt to provide an overview of the molecular design developed to tune the applicable properties and self-assembly of perylene derivatives as well as recent developments related to their application in the fabrication of organic solar cells, organic light-emitting diodes, and organic field-effect transistors.

Light-Bias Duel Modulation on Spin-Coated Zinc-Tin Oxide (ZTO) Thin Film Transistor

Zinc tin oxide (ZTO) is a transparent semiconductor based on earth-abundant elements. In this work, ZTO films prepared by spin coating via a solution route have been applied as the active semiconductor layer in a thin film transistor (TFT) with SiO2 dielectrics and Si gate. With thickness less than 10 nm, the ZTO film exhibits a good field-effect mobility of ~10 cm2/Vs, small subthreshold slope of ~0.5 V/decade and high on/off current ratio of ~107. Under light illumination of 405 nm wavelength (below ZTO bandgap), the photoresponse of ZTO TFT is related to the ionization of neutral oxygen vacancies to positively-charged oxygen vacancies, which simultaneously produce photogenerated electron carriers. With power density upto 1 mW/cm2, the light sensitivity is in the order of 105~106 for the ID-off region. The light responsibility of ZTO TFT reaches around 740 A/W. Additionally, the characteristics of 405nm light-gated ZTO TFT under different gate biases are investigated. The ionized oxygen vacancies generated by light illumination provide a positive electric field. As a result, it is possible to control the transistor with the incident optical power density instead of gate voltage. The drain current versus power density (ID-P) curve showed on/off switching behavior. Besides, the ID-VD curves of light-gated ZTO TFTs are similar to electricity-gated ones where ID increases linearly with increasing VD first and gets saturated after a certain VD value.

Rapid Formation and Macroscopic Self‐Assembly of Liquid‐Crystalline, High‐Mobility, Semiconducting Thienothiophene

AbstractA synergistic approach to enhance charge‐carrier transport in organic semiconductors along with facile solution processing and high performance is crucial for the advancement of organic electronics. The floating film transfer method (FTM) is used as a facile and cost‐effective method for the fabrication of large‐scale, uniform, highly oriented poly[2,5‐bis(3‐tetradecylthiophen‐2‐yl)thieno[3,2‐b]thiophene] (pBTTT C‐14) films under ambient conditions. Utilization of such oriented films as the active semiconducting layer in organic field‐effect transistors (OFETs) results in highly anisotropic charge‐carrier transport. Highly oriented, FTM‐processed pBTTT C‐14 thin films are characterized by polarized electronic absorption and Raman spectroscopy, atomic force microscopy, out‐of‐plane X‐ray diffraction, and grazing incident X‐ray diffraction (GIXD) measurements. The GIXD data indicate an edge‐on orientation, which is highly desirable for planar devices such as OFETs. OFETs built using the oriented films show a mobility anisotropy of 10 and the highest mobility is 1.24 cm2 V−1 s−1 along the backbone orientation, which is among the highest value reported for this class of materials using a similar device configuration.

Water‐Processable Multiwalled Nanotube: Phenol‐Induced Reversible Oxidation Process and Ambipolar Charge Transport Property

AbstractDue to the fascinating electronic, thermal, and mechanical properties of single‐walled carbon nanotubes (SWCNTs), extensive efforts have been devoted to the development of SWCNT‐based materials. These materials' semiconducting properties and related applications, such as field‐effect transistors (FETs), have been investigated by researchers for many years. However, despite the significant progress achieved, it remains challenging to separate semiconducting and metallic nanotubes from the mixtures of as‐grown SWCNTs. In a few studies, composites of water‐processable phenol formaldehyde resin/multiwalled carbon nanotubes (MWCNTs) have been found to exhibit a quasireversible oxidation process and to behave as semiconductors or field‐effect transistors. This finding has rarely been reported for MWCNTs, and it differs greatly from findings regarding intrinsic semiconductive SWCNTs. Significantly, field‐effect transistors fabricated with MWCNT composites as their semiconductor active layers have shown ambipolar charge transport characteristics. The results provide a high value‐added application pathway for the application of polymer/MWCNTs as the FET materials for electronic devices that offer higher performance at a lower cost.

FDTD based Plasmonic Light Trapping Analysis in Thin Film Hydrogenated Amorphous Silicon Solar Cells

For thin film solar cells, plasmonics is a novel light trapping technique based on light scattering due to metal nanoparticles through excitation of localized surface plasmons. The excited surface plasmon at the interface of a higher dielectric active semiconducting layer and the metal, by channelling incident radiations will trap light within the device for the higher optical path in physically thin structures resulting in enhanced photocurrent. In this paper, through FDTD based electromagnetic simulations, significance of controlled nanopatterning of silver (Ag) on the front side of p-i-n hydrogenated amorphous silicon for light absorption in the devices is analyzed. The analysis includes better control of nanoparticle parameters like size, shape, distribution and spacing for obtaining full benefits of plasmonic effects. It is demonstrated with an attractive strategy of fine tuning the nanostructures, incident light coupling with semiconductor ensures light confinement within the active layer promoting photon absorption across visible and near infrared regions.

Impact of unintentional oxygen doping on organic photodetectors

Oxygen plasma is a widely used treatment to change the surface properties of organic layers. This treatment is particularly interesting to enable the deposition from solution of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) on top of the active layer of organic solar cells or photodetectors. However, oxygen is known to be detrimental to organic devices, as the active layer is very sensitive to oxygen and photo-oxidation. In this study, we aim to determine the impact of oxygen plasma surface treatment on the performance of organic photodetectors (OPD). We show a significant reduction of the sensitivity as well as a change in the shape of the external quantum efficiency (EQE) of the device. Using hole density and conductivity measurements, we demonstrate the p-doping of the active layer induced by oxygen plasma. Admittance spectroscopy shows the formation of trap states approximately 350 meV above the highest occupied molecular orbital of the active organic semiconductor layer. Numerical simulations are carried out to understand the impact of p-doping and traps on the electrical characteristics and performance of the OPDs.

Contact engineering for efficient charge injection in organic transistors with low-cost metal electrodes

Controlling charge injection at the metal-semiconductor interface is very crucial for organic electronic devices in general as it can significantly influence the overall device performance. Herein, we report a facile, yet efficient contact modification approach, to enhance the hole injection efficiency through the incorporation of a high vacuum deposited TPD [N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine] interlayer between the electrodes and the active semiconducting layer. The device performance parameters such as mobility and on/off ratio improved significantly after the inclusion of the TPD buffer layer, and more interestingly, the devices with cost effective Ag and Cu electrodes were able to exhibit a superior device performance than the typically used Au source-drain devices. We have also observed that this contact modification technique can be even more effective than commonly used metal oxide interface modifying layers. Our investigations demonstrate the efficacy of the TPD interlayer in effectively reducing the interfacial contact resistance through the modification of pentacene energy levels, which consequently results in the substantial improvement in the device performances.